PS6-11. Effects of Rumen-inert Fatty Acids and Choline Supplementation on Ovarian Dynamics and Luteal Blood Perfusion in Angus Cows.

Abstract In cattle, reproductive success is determined by ovarian dynamics and luteal function. Supplementing dietary fats and methyl donors can influence ovarian dynamics, embryo quality, and pregnancy rate. Therefore, we evaluated a targeted dietary supplementation strategy including rumen-inert mono- and polyunsaturated fatty acids and rumen-protected choline to determine its impact on ovarian parameters. One hundred lactating Angus cows were stratified by body weight and body condition score and then randomly assigned on d -30 to a 2 × 2 factorial arrangement of treatments: CON) 116.5 g of saturated fatty acids, TARG) 115 g of rumen-inert mono- and polyunsaturated fatty acids, plus 60g of rumen-protected choline, FAT) 115 g of rumen-inert mono- and polyunsaturated fatty acids and CHO) 60 g of rumen-protected choline. Treatments were top-dressed daily onto the total mixed ration until d 30 post-insemination. All cows were synchronized using a 7-day CO-synch CIDR protocol and inseminated with semen from the same sire on d 0 by the same technician. Continuous and binomial data were analyzed using the GLIMIX procedure of SAS using preplanned contrasts to evaluate the main effect of fat source (TARG+FAT vs. CON+CHO), choline supplementation (TARG+CHO vs. CON+FAT), and their interaction (TARG+CON vs. FAT+CHO). The model included the fixed effects of treatments and the random effects of group and pen nested in group. Significance was declared at P ≤ 0.05. Follicle size on d 0 was 12.76 ± 0.37 mm for control, 12.64 ± 0.35 mm for CHO, 13.60 ± 0.57 mm for FAT, and 13.33 ± 0.58 mm for TARG (P ≥ 0.1146). Ovulation rate on d 14 was 83.51 ± 7.7 % for control, 79.92 ± 8.2 % for CHO, 92.04 ± 5.5 % for FAT, and 78.96 ± 8.6 % for TARG (P ≥ 0.2435). Luteal blood perfusion assessed by Doppler ultrasonography on d 14 was 50.45 ± 2.6 % for control, 52.85 ± 2.7 % for CHO, 49.91 ± 2.5 % for FAT, and 50.58 ± 2.7 % for TARG (P ≥ 0.5675). These preliminary outcomes indicate that maternal dietary supplementation with lipids, choline, or their combination did not alter ovarian dynamics or luteal blood perfusion. Ongoing investigations focus on hormonal analyses, uterine function, early embryonic development, and embryo-maternal communication.